Friction snubber for railway car truck springs



w. E. WITHALL FRICTION SNUBBER FOR RAILWAY CAR TRUCK SPRINGS May 29, 1951 Filed July 21, 1949 w w a u w w m W 1 W Q. Q? w w M6 02 I Z w x I 1 Ha n Inzren 1:- H jfall.

Patented May 29, 1951 FRICTION SNUBBER FOR RAILWAY CAR TRUCK SPRINGS William E. Withall, Hinsdale, 111., assignor to W. H. Miner, Inc., Chicago, 111., a corporation of Delaware Application July 21, 1949, Serial No. 106,033

4 Claims.

This invention relates to improvements in friction shock absorbers, especially adapted for use in connection with truck springs of railway cars for snubbing or dampening the action of the springs.

One object of the invention is to provide a friction shock absorber of the character indicated, including a casing, and a yieldingly resisted friction clutch, slidingl telescoped within the casing, including a wedge and cooperating friction shoes, wherein the wedge has its movement inwardly of the casing yieldingly opposed at the end of the compression stroke b means acting independently of the means which yieldingly resists movement of the shoes, to provide high resistance to absorb the heavier shocks at the end of the compression stroke of the mechanism and prevent oversolid compression of said mechanism.

A more specific object of the invention is to provide a friction shock absorber, comprising a casing, yieldingly resisted friction shoes slidingly telescoped within the casing a follower movable toward and away from the casing and having a wedge thereon in wedging engagement with. the shoes, wherein yielding cushioning means in the form of a rubber pad is carried on said follower, adapted to be compressed between'said follower and the casing during the last part of the compression stroke to absorb the excessively heavy shocks to which the mechanism is subjected in service and prevent direct engagement of the follower with the casing at the end of the compression stroke.

Other objects of the invention will more clearly appear from the description and claims hereinafter following.

In the accompanying drawing forming a part of this specification, Figure 1 is a vertical sectional view of my improved friction shock absorber, said section being taken on two intersecting planes 120 degrees apart and corresponding substantially to the line of Figure 2. Figure 2 is a top plan view of Figure 1. Figure 3 is a view similar to Figure 1, showing the mechanism fully compressed. Figure 4 is a broken, vertical sectional View, taken on the line 44 of Figure 2.

As shown in the drawing, my improved friction shock absorber comprises broadl a friction casing A, a follower B, a wedge C, three friction shoes DDD, a follower disc E, a rubber cushioning element F, and a rubber pad G carried by the follower B.

The friction easing A is in the form of a tubular member of substantially hexagonal, transverse cross section, open at its upper end and havins a transverse bottom wall 10 at its lower end. At the open upper end thereof, the side walls of the casing are inwardly thickened, as shown in Figures 1, 2, and 4, to provide a friction shell section H. The casing at said open upper end presents a substantially flat end surface l2 surrounding the op-ening thereof. The friction shell section H further presents three longitudinally extending, interior friction surfaces l3I3-|3 of V-shaped, transverse cross section, which converge inwardly of the casing. At said open upper end, the casing A has three interior stop lugs I l-J l-M, which are alternated with the three friction surfaces I3l3l3. The bottom wall 10 of the casing is provided with a central opening l5 therethrough, adapted to accommodate the usual spring centering projection of the bottom spring plate of a cluster of truck springs of a railway car.

The wedge C is formed integral with the follower B, the wedge being in the form of a hollow block and the follower B being in the form of a laterally outwardly projecting, annular flange at the outer end of the wedge. The follower B is of circular outline, and is provided with three circumferentially spaced openings l6--lB-l6 therethrough, outwardly of the wedge C, which are utilized in assembling the mechanism, as hereinafter pointed out.

The wedg C has three wedge faces I1-lll1 at its inner end, which are of V-shaped, transverse cross section, and converge inwardly or downwardly of the mechanism. At the inner or lower ends of the wedge faces lll1l'l, the wedge C has three laterally outwardly projecting, radial lugs Itl3-H3, which are alternated with the wedge faces, as clearly shown in Figure 2. In other words, the lugs l8-l8--l8 are arranged so that they are located between adjacent wedge faces and extend between adjacent shoes D--D to engage in back of the lugs li-MM of the casing and restrict outward movement of the wedge. The hollow wedge C presents an opening Is at the top thereof, adapted to accommodate the & usual spring centering projection of the top spring plate of a truck spring cluster,

The three friction shoes D--D-D are of similar design, each shoe having an outer, longitudinally extending, V-shaped friction surface 20, engaged with one of the V-shaped friction surfaces 23 of the casing A. On its inner side, each shoe is provided with an enlargement 2|, presenting a V-shaped wedge face 22, engaged with one of the wedge faces I? of the wedge C and correspondingly inclined thereto. At the inner or bottom end, thewenlargement of each shoe presents a transversely extending, fiat abutment face 23 on which the follower disc E is adapted to bear.

The rubber element F is in the form of an elongated, solid cylinder, slightly tapered toward its opposite ends, as shown in Figure 1. The element F is arranged within the casing A, below the friction shoes DD-D 'beingsu-pported on a disc-like plate 24, which, in turn,"is supported on the bottom wall H3 of the casing and closes the opening [5 of said wall. 'Iheelemen'tiF-supports the follower disc E, which is in the form of a flat plate buttressed against the abutment faces 23-33-23 of the shoes D-DD.

The rubber pad G is in the'form of a ring-like washer, surrounding the wedge C and vulcanized to the underneath face of the follower B. The pad "G has openings 25-Z525 therethrough, registering with'the openings |6l6-l'6 of the follower B, to provide continuous passages through said follower and pad to admit an assembling tool, as hereinafter pointed out. The rubber pad G extends to the periphery of the follower B and serves as a cushioning element between the follower B and the upper end of the casing Aduring the last part of the compression strokeof the mechanism.

In-ass'embling the mechanism, the rubber element F is first placed within the casing A in position resting on the plate 24. The follower disc E and the three shoes D'D- D are then placed in position on top of theelement F. Next, the wedge C, carrying the follower B and the attached padG, is placed on top of the shoes and turned so that the lugs -i8-I8-l8 of the wedge are circumferentially offset with respect to'the lugs l'-l4--l4 of'the casing so as to clear the latter when the wedge is moved inwardly of the casing. With the parts thus positioned, the shoes -DD--D are depressed by a suitable tool, having prongs inserted through the openings l'6-Hil6 of the follower B, to such an extent that the upper ends of the shoes reach a position below the lugs MI4l4 of the casing, which will provide suflicient clearance for rotary displacement of the lugs l8l'8l8 of the wedge C. With the parts held in this position, the wedge C is given a partial turn to bring the lugs l8l8l8 in back of the lugs -Hll'4--l4 of the casing in aligned position with the'last named lugs. With the wedge in this position, the shoes D-DD are freed from pressure by withdrawal of the assembling tool, and expansion of the rubber element F forces the shoes to their uppermost position, thereby locking the wedge against rotation and forcing the lugs lS-IB-l8 of the latter against the lugs l4l 4I l of the casing A.

My improved shock absorber preferably replaces one or more of the spring units of a truck spring cluster of a railway car, being interposed between the top and bottom spring plates of said cluster.

The operation of my improved shock absorber is as follows: Upon the spring cluster of-thetruck 4 of a railway car being compressed between the spring follower plates of the cluster, the wedge C and the follower B are forced downwardly with respect to the casing A, the wedge spreading the shoes apart and carrying the same inwardly of the casing, against the resistance of the rubber element F, thereby providing progressively increasing resistance as the mechanism is com- 7 pressed. During this action, the follower B, with the attached rubber pad G, approaches the top of the friction casing, the rubber pad G being forcibly pressed ,againstthe upper end of the casing during the last part of the compression stroke of the mechanism to add its resistance to that of the yieldingly resisted friction shoes to take care of the heavier final shocks. Figure 3 shows-the rubber pad G being compressed between the fiat end surface i2 of the casing and thefollower B. As will be evident, the rubber pad G prevents the follower B from gcing solid against the friction casing and provides cushioningaction to the end of the compression stroke. Upon recoil of the truck springs, the actuating force onthe follower B and wedge C is reduced, and lengthwise expansion of the rubber element F, in returning'to its original shape, returns all of the parts to the normal :position shown in Figure 1. Release of the mechanism is initiated by the expansive action .of the rubber pad G, which acts to force the wedge C away from the shoes -D- D-+D to reduce .the wedging pressure.

I claim:

'1. "In a friction shock absorber, the combina tion with :a friction casing open at one end; of friction shoes slidingly telescoped within said open end of the casing; a follower .movable toward the casing; a rubber pad on said follower engageable with :the open end of said casing after a predetermined amount of..c'ompression of mechanism to be compressed between said follower and easing; a wedge movable toward the casing in unison with said follower, said Wedge being in wedging engagement with the shoes; and yielding means within the casing opposing inward movement of said shoes independently of said rubber pad.

'12. In a friction shock absorber, the, combi nation with a friction :casing; of friction shoes sl'idinglytelescoped within the casing; a wedge in wedging engagement with the shoes; a follower rigid with said wedge; a rubber pad on said follower, .surrounding said wedge, said follower wedge being movable toward and away from the casing, said'follower, after movement to a predetermined ext'ent toward. said casing, forcing saidilpad against the casing to com-press said pad; and a rubber :block within the casing yieldingly opposing inward movement of, the.- shoes.

3. In a friction shock .abscrbenthe combination with aifricti'on :cas'ing open at its upper end; of friction shoes slidingly telescoped within the open end of the casing; 1a follower above said casing movable toward and away from the same; a'rubber pad of-the underneath side of said fol lower en'gageable with the casing after the mechanism has been compressed to a predetermined extent; a wedge block fixed with respect to said follower and having wedging engagement with said shoes; and a'rubber block within the casing yieldingly opposing inward movement of said shoes. i

4. In a friction shock absorber, the combination with a friction casing open at one end; of a friction clutchslidingly telescoped within said open end of the casing, said" clutch including a follower opposed to the open end of said casing; a rubber annulus on the inner side of said follower in alignment with the wall of said casin at said open end and engageable with the outer end of said wall after the mechanism has been 6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Barrows Jan. 15, 1935 Babbitt Sept. 2, 1941 Cottrell Mar. 10, 1942 Qath Dec. 7, 1943 Thornhill Aug. 22, 1944 Freeman Nov. 12, 1946 Bath May 10, 1949 

